1. Field of the Invention
The invention relates to power supplies and, in particular, to a modularized low voltage, high current power supply with improved performance.
2. Description of the Prior Art
The military has demanded that its suppliers develop systems using replaceable standard electronic modules (SEMs) as building blocks in various avionics packages. In general, SEMs standardize the size, interface, and configuration of various units within a system. This, in turn, eases rework in the field, reduces costs and eases equipment upgrades. Further, modules can be pulled out and replaced with new ones without having to redesign or change the rack or the chassis. Because every rack in a system requires power, the development of a low cost, high reliability so-called SEM-E format low voltage power supply (LVPS) having a high current capability is an important step in the accomplishment of modularity.
Overall, SEM format "E" packages conform to a 6.4".times.5.88".times.5" outline with wedge locks on opposite narrow rails, a distal connector bus and a proximate extractor. Any particular design must fit all the components into the specified outline and provide good thermal management while at the same time meeting military specifications and cost restraints.
Low voltage power supply (LVPS) efficiency is degraded by the internal conduction losses occurring in the distribution of typically high currents through such systems. The high current manifests itself in heat loss in the various power supply components, including power switches, magnetic devices, rectifiers, transformers and the bus bars. The heat generated causes elevated temperature which in turn degrades reliability and efficiency.
A conventional LVPS contains a large number of interconnects usually round wires and various connectors. There are also numerous separate components required to regulate and control the various power supply functions. These factors increase cost and degrade reliability and result in volume inefficiencies.
Among the most complex and costly components are magnetic assemblies for transformers and inductors. These components are traditionally labor intensive and difficult to manufacture consistently with a high yield.